Comparison of different diluents based on liposomes and egg yolk for ram semen cooling and cryopreservation.

BACKGROUND: Sperm cryopreservation is an important tool for breed improvement, nonetheless, spermatozoids of rams are extremely sensitive to cryopreservation. AIMS: The present research was to compare a liposome-based (OptiXcell: OX) diluent, a commercial TRIS-egg yolk (Optidyl: OP) and a citrate egg yolk-based (CY) diluent on ovine semen quality through the cryopreservation process. METHODS: Semen was collected from four sexually mature Dorper rams during the natural breeding season. After collection, semen was evaluated and diluted in OX, OP or CY diluent and was cooled from 37°C to 4°C for 2 h (refrigerated semen, RS), after that semen-filled straws were placed in liquid nitrogen (LN) vapour for 10 min, then immersed into LN at -196°C (cryopreserved semen, CS) and stored until evaluation. RESULTS: For fresh semen (FS), similar values (P>0.05) were obtained from the 3 diluents [motility (4.2 ± 0.3), viability (75.4 ± 3.2), hypo-osmotic swelling test (HOST) (59.2 ± 2.1), and normality (84.7 ± 3.5)]. The motility values were higher for RS with OX and CY (4.0 ± 0.2 and 3.6 ± 0.3, respectively) compared to OP (3.0 ± 0.21; P<0.05). The viability was reduced after refrigeration and freezing (P<0.05). Refrigerated semen viability was similar for OX (65%), CY (63%) and OP diluents (60%; P>0.05), but for frozen semen, viability was lower in the CY diluent (P<0.05). Membrane integrity (HOST) in OX (53.6 ± 1.7) was similar to that in OP (50.7 ± 1.5; P>0.05) but higher than in CY (48.7 ± 1.5; P<0.05). CONCLUSION: No difference was found between the OX diluents and those made with egg yolk in terms of sperm parameters; however, the OX diluent was more efficient in protecting the integrity of membrane in freezing/thawing semen.

Exposure of sexually inactive males to estrogenized females increased the investigative and consummatory sexual behavior.

Two trials were conducted to evaluate the effect of diverse socio-sexual cues upon male sexual behavior and the reproductive performance of anestrous does (AD). Trials were conducted in northern Mexico (26°N) during the natural anestrous season (Feb-Mar) with crossbred dairy bucks. In Experiment 1, sexually inactive bucks (SIB, n=12) were randomly allotted to three groups, four males/group: a) DEE 9novelty stimulation) - daily exchange of estrogenized females (EF) 12&12h, b) NEE (no novelty stimulation) - no-exchange of EF, 24h, or c) CON (saline-treated_ -daily exchange of AF 12&12h. Sexually active bucks (SAB) from the DEE, NEE and CON groups were subsequently exposed to AD (n=72; n=24/group) and the reproductive outcomes were recorded. In Experiment 2, SAB (n=12; n=6/group) were randomly divided in: 1) B+EF - males+four-EF exposed to AF (n=36), and 2) B+NEF; males+four-saline-treated AD and exposed to AD (n=36). Prior to the onset of the experimental breeding in both experiments, the investigative (ISB), consummatory (CSB) and resting (RSB) sexual behavior of males were quantified (2h×d×2d). Sexual behaviors considered were: ISB - flehmen, ano-genital sniffing, approaches, vocalizations, kicking, penis extrusion, CSB; mount attempts and mounts, and RSB - isolation, attempted escape, aggression and distractions. While EF were an effective stimulus (P<0.05) for evoking mounting in SIB males, daily exchange of estrous does used to stimulate males promoted an enhanced response (P<0.05) in terms of both ISB and CSB. After being exposed to AD, the B+EF bucks induced an earlier estrous response (P<0.05) as compared with the B+NEF bucks. The untreated females did not induce any sexual activity in males and stimulation of ovarian function did not occur when saline treated (CON) AD were exposed to AD. Also, the B+EF group induced an enhanced increase (P<0.05) of the male ISB and CSB, inducing in turn an increase percentage onset of estrus in does that had previously been anestrus (P<0.05).

Effects of supplementation during late gestation on goat performance and behavior under rangeland conditions.

This study evaluated the effects of peripartum feed supplementation on doe and kid BW and BCS, milk yield and composition, serum metabolites, and maternal-neonatal behavior under rangeland conditions in northern Mexico. Adult does ( = 23) were randomly assigned to 3 nutritional plane groups: 1) goats supplemented (500 g of concentrate [18% CP/kg DM, 2.7 Mcal/kg DM, and 2% salt]) from 15 d prepartum to 7 d postpartum (G15; = 8), 2) the same supplementation as G15 but from 35 d before until 7 d after kidding (G35; = 8), and 3) nonsupplemented does (GC; = 7). Supplemented goats differed from GC goats in BW (48 ± 1.8, 46.1 ± 2.5, and 44.9 ± 2.3 kg; < 0.05), milk yield (1.8 ± 0.1, 1.9 ± 0.2, and 1.2 ± 0.1 kg at d 15 postpartum; < 0.01), kid birth weights (3.8 ± 0.2, 3.6 ± 0.2, and 3.4 ± 0.2 kg; < 0.05), and kid BW at 15 d after birth (6.9 ± 0.2, 6.6 ± 0.2, and 5.6 ± 0.2 kg; < 0.05) for the G35, G15, and GC, respectively. Serum concentrations for total protein, glucose, and cholesterol were not affected ( > 0.05) by treatments. Milk of GC goats showed increased ( < 0.05) percentages for fat, protein, lactose, and nonfat milk solids, whereas total quantities of these variables where higher ( < 0.05) in the G15 and G35 groups. Furthermore, GC dams spent more time seeking their offspring and emitted more low-pitched bleats 4 h postpartum ( < 0.05) in a 2-choice test compared with the G15 and G35 groups. In general, peripartum supplementation promoted a closer dam-kid relationship at 8 h postpartum. Goat performance may be improved in this semiarid region of Mexico with marginal production through supplementation in late gestation.

Parity of female goats does not influence their estrous and ovulatory responses to the male effect.

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1,900 h, a group of multiparous females (n=21) and a group of 16 months-old nulliparous females (n=19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1,830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ (P>0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ (P>0.05) between multiparous (1.9+/-0.1 days) and nulliparous (1.7+/-0.2 days) females. The proportion of females displaying a short estrous cycle was greater (P<0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ (P>0.05) between groups (multiparous: 5.2+/-0.3 days, nulliparous: 4.5+/-0.1 days). The number of anogenital sniffings was greater (P<0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater (P<0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different (P>0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.